1. Field of the Invention
The present invention relates to a high-frequency module for transmitting and receiving a plurality of communication signals having different frequency bands that includes a switch integrated circuit (IC).
2. Description of the Related Art
Various types of high-frequency modules including switch ICs have been proposed. For example, Japanese Unexamined Patent Application Publication No. 2008-516494 discloses a high-frequency module including a switch IC including six individual terminals for a single common terminal connected to an antenna. Each of the six individual terminals of the switch IC is connected to one of a transmission circuit, a reception circuit, and a transmission/reception circuit used for a plurality of communication signals having different frequency bands. In the high-frequency module configured as described above, the switch IC is driven to switch the connection between the common terminal and the individual terminals, thereby connecting the antenna to the transmission circuit, the reception circuit, or the transmission/reception circuit used for a specific communication signal.
In each transmission circuit of the known high-frequency module, a filter is provided to attenuate second and third harmonics of a communication signal, i.e., a transmission signal, having a transmission frequency generated in the previous circuit. Along with this filter, an electro-static discharge (ESD) protection circuit is provided for the high-frequency module and includes a portion that is disposed close to the antenna.
Currently, the performance of mobile communication devices having a high-frequency module mounted thereon, such as the above-described high-frequency module, needs to be improved, and it is desired that one antenna be used for many communication signals. In this case, if a filter is provided for each communication (transmission) signal, it is difficult to reduce the size of the high-frequency module.